Transfered Binary size optimisation

In case of big pictures, videos etc, it doesn't make sense to send the full res file to ARender. We want to review how the connector works so as to rely on a kind of "ARender rendition" to send the binary to ARender. 

Note that this can work only on mime-types / kind of files  for which ARender doesn't have too specific conversion skills (ex: extracting layers of a PSD).